DIDA® uses "PCVD" to maximize performance and durability. This latest scientific "State of the Art" technology creates a hard wear resistant, low friction film. Our steel alloy piston ring is coated with "PCVD" while our cylinder is coated with a hard durable ceramic coating. Together they reduce friction and form a clean burning system that generates more power, while ensuring longer life. In addition to these features our "HEMI" head design makes this saw the most powerful in its class.